Congress’s chief budget scorekeeper told senators on Wednesday that ferreting out government inefficiencies is a worthwhile goal, but tackling federal deficits in a meaningful way will require more than nibbling around the edges.

“Improving the efficiency of government is an important objective, but being CBO, I have to mention that given an aging population and rising health care costs, making a significant dent in federal deficits would require broader changes in federal tax or spending policies,” Keith Hall, director of the Congressional Budget Office, told members of the Senate Budget Committee.

“To make such changes, lawmakers would have to increase revenues above amounts projected under current law, reduce spending for larger benefit programs such as social security [and] Medicare, or combine these approaches,” he said.

Gene Dodaro, comptroller general of the Government Accountability Office (GAO), said that since 2003, the cumulative amount of improper payments within programs like Medicare and Medicaid are in excess of $1.2 trillion, and the total is estimated to have topped $100 billion in each of the last three years.

But even trying to get at fixing those problems is another matter, he said.

“For a number of years now, we identified a material weakness in our audits of the federal government’s financial statements on improper payments that the federal government really is not able to determine the extent of this problem across the government, or to have a reasonable prospect that it’s managing it properly to reduce these improper payments,” he said.

The two men were testifying at a Senate Budget Committee hearing on how to make the federal government work more effectively and efficiently.

“It’s important for Congress to ask if we are using taxpayer dollars wisely, and operating the government as efficiently and effectively as the managers of a private sector company would,” said Sen. Mike Enzi, Wyoming Republican and chairman of the panel.